The miniature video camera is more and more widely used because of its small size. At present, there exist video cameras with means for fixing the camera head to a human's head. (for example, buckle fastener, ear-hook, etc.) This kind of video cameras are generally used in outdoor activities, such as cycling, climbing, etc. However, this kind of video cameras have the following defects: the users can not communicate with the outside in real-time during outdoor activities, which is not very convenient for the users.